Rigid-Flex PCB Layout for Wearable Slot Antenna Interference

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Solution Overview

Problem

The presence of a metal frame in wearable electronic devices affects antenna performance due to interference from adjacent printed circuit boards.

Innovation Solution

Incorporating a rigid flexible printed circuit board with a non-conductive portion and conductive traces that extend from a fill-cut region to improve slot antenna performance by radiating signals through a gap between the metal frame and display panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a printed circuit board is disposed adjacent to the metal frame, then electronic circuits can obtain external information through the metal frame, but the printed circuit board affects antenna performance

Engineering Contradiction:
Improveease of obtaining external informationVSAvoidantenna performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The rigid portion of the printed circuit board is divided into a first portion and a second portion. The first portion is positioned under the electronic circuitry away from the antenna slot, while the second portion extends toward the display and is disposed on the side surface of the bracket. This segmentation allows the circuit board to maintain electrical connectivity while reducing interference with the metal frame antenna, thereby resolving the contradiction between ease of obtaining external information and antenna performance reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second portion of the rigid portion is configured with specific local properties: it extends from the first portion toward the display, is disposed on the side surface of the bracket, and includes a non-conductive portion arranged with respect to the slot between the metal frame and the display panel. This local quality modification allows the circuit board to maintain its information acquisition function while minimizing interference with the antenna slot, thus resolving the technical contradiction.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If the rigid portion is positioned close to the metal frame for compact design, then device size is reduced, but signal radiation through the slot is interfered with

Engineering Contradiction:
Improvedevice sizeVSAvoidsignal radiation efficiency
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The second portion of the rigid portion is configured with specific local properties: it extends from the first portion toward the display, is disposed on the side surface of the bracket, and includes a non-conductive portion arranged with respect to the slot between the metal frame and the display panel. This local quality modification allows the circuit board to maintain its information acquisition function while minimizing interference with the antenna slot, thus resolving the technical contradiction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The second portion of the rigid portion is disposed on the side surface of the bracket, utilizing the vertical dimension rather than extending horizontally toward the metal frame. This dimensional repositioning allows the circuit board to maintain compact device size while avoiding interference with the slot antenna radiation, effectively resolving the contradiction between device volume and signal radiation efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances antenna performance by minimizing interference and optimizing signal radiation efficiency.

Implementation Method 1

a slot antenna at least partially formed by a gap between the metal frame and the display panel... The slot antenna radiates radio waves using the gap extended by the fill-cut region

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP4707959A1Wearable electronic device comprising rigid-flexible printed circuit board
Publication Date: 2026.03.11 SAMSUNG ELECTRONICS CO LTD
  • EP4707959A1 patent drawingFigure 1
  • EP4707959A1 patent drawingFigure 2
  • EP4707959A1 patent drawingFigure 3

AI summary

A wearable electronic device is provided. The wearable electronic device comprises: a housing comprising a metal frame; a display inside the housing; a bracket inside the housing, comprising a side surface facing the inner surface of the metal frame; a rigid-flexible printed circuit board comprising a rigid portion positioned between the inner surface of the metal frame and the side surface of the bracket; and an electronic circuit on the rigid portion, wherein the rigid portion comprises a first portion below the electronic circuit, and a second portion extending from a portion of the first portion toward the display and disposed on the side surface of the bracket such that the rigid portion is supported by the bracket, and the second portion may comprise a non-conductive portion arranged with respect to a slot between the metal frame and a portion of the display and used to radiate a signal to an external electronic device.